Collapsible shelf assembly

ABSTRACT

A collapsible shelf assembly having four detachable, slideably mated trays, each tray comprising an L-shaped superiorly-rising sidewall in some embodiments. The collapsible shelf assembly is adapted to collapse (or retract) along two axes to facilitate adjustment of shelf width and depth to optimize volume usage to users needing shelving providing adjustable surface area.

FIELD OF THE INVENTION

This invention relates to shelving and refrigeration apparti, and moreparticularly relates to foldable, collapsible or retractable shelvingfor optimizing storage space for perishable goods.

BACKGROUND Description of the Related Art

Cooler and freezer shelving assemblies and shelves for storage ofhand-sized articles and perishable goods, as well as other small items,are well-known in the art. Such shelving structures are often fabricatedfrom polymeric materials, metal or wood; and are usually fabricated anddimensioned to position within the walls of refrigerators, freezers,coolers and interior and exterior shelving. Traditional shelves maydispose between partitions, wall or vertical supports within a largerstructure such as refrigerator. Typically, these shelves slide onto orinto spacing brackets or slots defined by walls, partitions or verticalsupports. These traditional shelves include slotted angle shelves andpipe shelves.

However, traditional shelves are typically very generic in shape,usually consisting of little more than an open-topped or open-front binin which the goods such as food perishables are stacked. Traditionalshelving consists of a concave or tray-shaped open top with upwardlyprotruding sidewalls meant to secure articles, chattels and goods fromoverspilling laterally off shelf sides.

In both commercial and residential applications, volume, horizontalspace and vertical space are limited, particularly within coolers andrefrigeration apparati which are well insulated and expensive. Polymericmaterials are favored for shelving over wood and metal in theseenvironments because they insulate and are rust and corrosion resistant.Users of shelves often find the shelving itself is blocking the userfrom storing items of only slightly too high or broad dimension, such amilk cartons, pizza boxes, bags, bottles, and the like.

Although shelves are known in the art which are adjustable verticallyrelative to other shelving, and shelves are known in the art whichslidably affix to mounting brackets or telescoping sidetracks, shelvingwhich collapses along one or two axes is unknown in the art. Theinconvenience and difficulty encountered by individuals attempting tomake optimal use of vertical and horizontal storage space could besubstantially alleviated if a device which overcomes these shortcomingsin the art were available, including shelving which retracts along twoaxes. There is a substantial need for a means of curing thesedeficiencies in the art.

As such, it would be desirable to provide a collapsible shelf in someaspect adapted to retract on two axes, while retaining an economicalconfiguration that is also relatively easy to use and manipulate in bothcollapsed (or retracted) and open positions. It is therefore an objectof the present invention to provide a collapsible shelf structurespecifically adapted in one aspect for a refrigeration unit to optimizespace and storage internally according to the needs of a user.

SUMMARY

From the foregoing discussion, it should be apparent that a need existsfor a collapsible shelf assembly. Beneficially, such a device wouldovercome inefficiencies with the prior art by providing an inexpensive,efficient means of optimizing space for chattels by providing for shelfretraction along two or more axes.

The present invention has been developed in response to the presentstate of the art, and in particular, in response to the problems andneeds in the art that have not yet been fully solved by currentlyavailable apparti. Accordingly, the present invention has been developedto provide a collapsible shelf assembly, the collapsible shelf assemblycomprising: a first tray defining two or more laterally-running guidetracks, the first tray comprising: a generally rectangular base memberfabricated of rigid polymeric material; a first sidewall affixed to atop surface of the base member, the first sidewall superiorly-protrudingtherefrom adapted provide lateral stability to articles stored on thetop surface; a second sidewall affixed to a top surface of the basemember, the second sidewall superiorly-protruding therefrom adaptedprovide lateral stability to articles stored on the top surface; two ormore protuberances adapted to slidably travel within a longitudinalguide track on an adjacent tray running perpendicularly to thelaterally-running guide tracks; a second tray defining one or morelaterally-running guide tracks and one or more longitudinally-runningguide tracks, the second tray comprising: a generally rectangular basemember fabricated of rigid polymeric material; a first sidewall affixedto a top surface of the base member, the first sidewallsuperiorly-protruding therefrom adapted provide lateral stability toarticles stored on the top surface; a second sidewall affixed to a topsurface of the base member, the second sidewall superiorly-protrudingtherefrom adapted provide lateral stability to articles stored on thetop surface; a third tray defining one or more longitudinally-runningguide tracks, the third tray comprising: a generally rectangular basemember fabricated of rigid polymeric material; a first sidewall affixedto a top surface of the base member, the first sidewallsuperiorly-protruding therefrom adapted provide lateral stability toarticles stored on the top surface; a second sidewall affixed to a topsurface of the base member, the second sidewall superiorly-protrudingtherefrom adapted provide lateral stability to articles stored on thetop surface; two or more protuberances adapted to slidably travel withina laterally-running guide track on an adjacent tray; a fourth traycomprising: a generally rectangular base member fabricated of rigidpolymeric material; a first sidewall affixed to a top surface of thebase member, the first sidewall superiorly-protruding therefrom adaptedprovide lateral stability to articles stored on the top surface; asecond sidewall affixed to a top surface of the base member, the secondsidewall superiorly-protruding therefrom adapted provide lateralstability to articles stored on the top surface; four or moreprotuberances adapted to slidably travel within one or more guide trackson an adjacent trays.

The base member, first sidewall and second sidewall of each tray may beformed as a single integrated piece.

The base member of each tray may be perforated. Each tray may beinsulated. The protuberances, in some embodiments, are substantially oneof cylindrical and conical. The trays may form a friction fit one withanother in a collapsed configuration.

A collapsible shelf is also provided, the collapsible shelf comprising:a first tray defining one or more laterally-running guide tracks, thefirst tray comprising: a planar base member fabricated of rigidpolymeric material; a first sidewall affixed to a top surface of thebase member, the first sidewall superiorly-protruding therefrom adaptedprovide lateral stability to articles stored on the top surface; asecond sidewall affixed to a top surface of the base member, the secondsidewall superiorly-protruding therefrom adapted provide lateralstability to articles stored on the top surface; a second tray definingone or more longitudinally-running guide tracks, the second traycomprising: a planar base member fabricated of rigid polymeric material;a first sidewall affixed to a top surface of the base member, the firstsidewall superiorly-protruding therefrom adapted provide lateralstability to articles stored on the top surface; a second sidewallaffixed to a top surface of the base member, the second sidewallsuperiorly-protruding therefrom adapted provide lateral stability toarticles stored on the top surface; a third tray defining one or morelongitudinally-running guide tracks, the third tray comprising: a planarbase member fabricated of rigid polymeric material; a first sidewallaffixed to a top surface of the base member, the first sidewallsuperiorly-protruding therefrom adapted provide lateral stability toarticles stored on the top surface; a second sidewall affixed to a topsurface of the base member, the second sidewall superiorly-protrudingtherefrom adapted provide lateral stability to articles stored on thetop surface; a track for slidably engaging one of alongitudinally-running guide track and a laterally-running guide trackon an adjacent tray; a fourth tray comprising: a planar base memberfabricated of rigid polymeric material; a first sidewall affixed to atop surface of the base member, the first sidewall superiorly-protrudingtherefrom adapted provide lateral stability to articles stored on thetop surface; a second sidewall affixed to a top surface of the basemember, the second sidewall superiorly-protruding therefrom adaptedprovide lateral stability to articles stored on the top surface; a trackfor slidably engaging one of a longitudinally-running guide track and alaterally-running guide track on an adjacent tray.

Each tray may slidably mate with two other trays.

The base member, first sidewall and second sidewall of each tray may beformed as a single integrated piece.

Another collapsible shelf is provided, the collapsible shelf comprising:a first tray defining one or more guide tracks, the first traycomprising: a planar base member fabricated of rigid polymeric materialhaving four sides; an L-shaped sidewall affixed to a top surface of thebase member, the L-shaped sidewall superiorly-protruding therefrom andcovering two of the four sides of the base member; a second traydefining one or more guide tracks, the second tray comprising: a planarbase member fabricated of rigid polymeric material having four sides;one or more guide tracks for slidably receiving track on an adjacenttray; a third tray defining one or more guide tracks, the third traycomprising: a planar base member fabricated of rigid polymeric materialhaving four sides; an L-shaped sidewall affixed to a top surface of thebase member, the L-shaped sidewall superiorly-protruding therefrom andcovering two of the four sides of the base member; a fourth traydefining one or more guide tracks, the fourth tray comprising: a planarbase member fabricated of rigid polymeric material having four sides; anL-shaped sidewall affixed to a top surface of the base member, theL-shaped sidewall superiorly-protruding therefrom and covering two ofthe four sides of the base member; wherein each tray slidably mates withtwo other trays.

The base member, first sidewall and second sidewall of each tray may beformed as a single integrated piece.

Reference throughout this specification to features, advantages, orsimilar language does not imply that all of the features and advantagesthat may be realized with the present invention should be or are in anysingle embodiment of the invention. Rather, language referring to thefeatures and advantages is understood to mean that a specific feature,advantage, or characteristic described in connection with an embodimentis included in at least one embodiment of the present invention. Thus,discussion of the features and advantages, and similar language,throughout this specification may, but do not necessarily, refer to thesame embodiment.

Furthermore, the described features, advantages, and characteristics ofthe invention may be combined in any suitable manner in one or moreembodiments. One skilled in the relevant art will recognize that theinvention may be practiced without one or more of the specific featuresor advantages of a particular embodiment. In other instances, additionalfeatures and advantages may be recognized in certain embodiments thatmay not be present in all embodiments of the invention.

These features and advantages of the present invention will become morefully apparent from the following description and appended claims, ormay be learned by the practice of the invention as set forthhereinafter.

BRIEF DESCRIPTION OF THE DRAWINGS

In order that the advantages of the invention will be readilyunderstood, a more particular description of the invention brieflydescribed above will be rendered by reference to specific embodimentsthat are illustrated in the appended drawings. Understanding that thesedrawings depict only typical embodiments of the invention and are nottherefore to be considered to be limiting of its scope, the inventionwill be described and explained with additional specificity and detailthrough the use of the accompanying drawings, in which:

FIG. 1 is an upper side perspective view of a disassembled collapsibleshelf assembly in accordance with the present invention;

FIG. 2 is a lower side perspective view of an assembled collapsibleshelf assembly in the open position in accordance with the presentinvention;

FIG. 3 is an upper side perspective view of a disassembled collapsibleshelf assembly in accordance with the present invention;

FIG. 4 is an upper side perspective view of an assembled collapsibleshelf assembly in the open position in accordance with the presentinvention;

FIG. 5 is a lower perspective view of an assembled collapsible shelfassembly in a partially-retracted position accordance with the presentinvention;

FIG. 6 is a lower perspective view of an assembled collapsible shelfassembly in a partially-retracted position accordance with the presentinvention;

FIG. 7 is an upper side perspective view of an assembled collapsibleshelf assembly in a partially-retracted position accordance with thepresent invention;

FIG. 8 is a side perspective view of an assembled collapsible shelfassembly in a partially-retracted position accordance with the presentinvention; and

FIG. 9 is a side perspective view of an assembled collapsible shelfassembly in a partially-retracted position accordance with the presentinvention.

DETAILED DESCRIPTION

Reference throughout this specification to “one embodiment,” “anembodiment,” or similar language means that a particular feature,structure, or characteristic described in connection with the embodimentis included in at least one embodiment of the present invention. Thus,appearances of the phrases “in one embodiment,” “in an embodiment,” andsimilar language throughout this specification may, but do notnecessarily, all refer to the same embodiment.

Furthermore, the described features, structures, or characteristics ofthe invention may be combined in any suitable manner in one or moreembodiments. In the following description, numerous specific details areprovided to provide a thorough understanding of embodiments of theinvention. One skilled in the relevant art will recognize, however, thatthe invention may be practiced without one or more of the specificdetails, or with other methods, components, materials, and so forth. Inother instances, well-known structures, materials, or operations are notshown or described in detail to avoid obscuring aspects of theinvention.

FIG. 1 is an upper side perspective view of a disassembled collapsibleshelf assembly 100 in accordance with the present invention. The shelf100 is formed from four trays 102, 104, 106, 108 which engage oneanother slidably to form a receptacle for storing chattels or perishablefoods. The shelf 100 is adjustable in width and depth to increase ordecrease the surface area of the shelf 100 available to users forstorage of implements, articles, chattels or perishables.

The shelf 100 comprises a first tray 102 having planar base member 118defining a plurality of holes, apertures, or bores 116 a-b for drainingstanding fluids collecting on the top surface of the first tray 102. Theapertures 116 may be round, ovoid, square, hexagonal or any other shape.The trays 102, 104, 106, 108 may be punches or perforated with holes orapertures 116.

The base member 118 is shown as a generally square or rectangular planarlower member which smoothly transitions at two of its peripheral edgesto one or more superiorly-rising planar or L-shaped peripheral sidewalls302 (also called “retention members” and further described below inrelation to FIGS. 3 and 4). The L-shaped sidewall 302 may comprise, insome embodiments, two separate planar sidewalls 402, 404 which mate orjoin together at the corner of the base member 118 forming a corner. Theperipheral side 302 acts to laterally stabilize articles such asperishable food items stowed or stored in the shelf 100.

The base member 118 is preferably square or rectangular, but may becircular, ovoid, elliptical, or irregularly-shaped.

The tray 102 forms one or more guide tracks 110 for slidably receivingadjacent trays 104, 106, 108. The tray 102 defines one or more lateralguide tracks 110 within the base member 118 which allow correspondingtracks on adjacent trays 104, 106, or 108 to travel. The lateral guidetracks 110 may be recessed into the bottom surface of the tray 102. Thelateral guide tracks 110 provide axial and lateral stability to anadjacent tray 108 as it travels on the X axis of the shelf 100 and areadapted to facilitate retraction of the tray 108 inward (or collapse ofthe shelf 100). The tray 108 overlaps or underlaps the tray 102. Theterm “guide track” is used interchangeably herein with “positioningslot.” The guide tracks 110, 114 may affixed using means known to thoseof skill in the art to the base member 118.

The tray 102 also may define, in some embodiments, one or morelongitudinal guide tracks 114 within the base member 118 which allowcorresponding tracks on an adjacent tray 104 to slide or travel withinthe tray 102. The longitudinal guide tracks 114 may be recessed into thebottom surface of the tray 102 and positioned in perpendicularorientation to the lateral guide tracks 110. The longitudinal guidetracks 114 provide axial and longitudinal stability to an adjacent tray104 as it travels on the Y axis of the shelf 100 and is adapted tofacilitate retraction of the tray 104 inward. The tray 104 also mayoverlap or underlap the tray 102.

In various embodiments, the longitudinal tracks 114 sit flush with thebase member 118 and comprise upwardly- or downwardly-protruding tabs 120(or protuberances 120) which insert into guide tracks on adjacent trays104-108 (further described below in relation to FIG. 2 and otherfigures). In other embodiments, the lateral and/or longitudinal tracks110, 114 are reliefed or recessed from the base member 118.

In various other embodiments of the present invention, the tray 102comprises integrated male tracks for slidably inserting within guidetracks on adjacent tray and permits travel of the tray 102 along the Xand/or Y axes of adjacent trays 104, 106, 108.

It is an object of the present invention to provide trays 102-108adapted to collapse or retract inwardly upon themselves with other trays102-108 of the shelf 100 with minimal tensile force, and also to openwhen retracted and return to an open position. The trays 102-108 aredetachable from one another by sliding each tray 102-108 in sequence outof a single adjacent tray 102-108 to which it is slidably affixed. Invarious embodiments, the trays 102-108 are spring-biased to return to anopen position when tensile or compressive forces on the shelf 100 arereleased.

FIG. 2 is a lower side perspective view of an assembled collapsibleshelf assembly 200 in the open position in accordance with the presentinvention.

The guide tracks 110 partially span the width (X axis dimension) of thetray 102, 104 and terminate at a side of the tray 102 uncovered by aperipheral sidewall 302, 402, 404 in some embodiments. In otherembodiments, two or more tabs 120 on adjacent trays 104-108 insert intothe guide tracks 110 and travel therein. The tabs 120 may besubstantially cylindrical or conical and may comprise flanges at theirterminal ends. In some embodiments, the tabs 120 comprise bolts orscrews affixed to the base member 118 or other tray 104-108 planarsurfaces, with the flanges being the heads of the bolts or screws.

The tabs 120 position within the guide tracks 110, 114. The male tracksslidably engaging the guide tracks 110, 114 may consist of one, two, orthree or more tabs 120.

In various embodiments, a sidewall spans one more sides of each tray102, 104, 106, 108 and is affixed therewith using, in less preferredembodiments, Velcro®, adhesive or other means known to those of skill inthe art, but preferably formed as an integrated piece.

The top edge of each peripheral sidewall 302, 402, 404 may be smooth,planar, or undulating.

The base member 118 may square in some embodiments. The correspondingbase members of other trays 102-108 may dimensioned such that they aremore substantially rectangular than the tray 102. For instance, tray 104is dimensioned such that its width is longer rationally to its depththan tray 102. Likewise, trays 106, 108 may also be so dimensioned invarious embodiments.

FIG. 3 is an upper side perspective view of a disassembled collapsibleshelf assembly 300 in accordance with the present invention.

In various embodiments, the peripheral sidewall 302 is formed with thebase member 118 of the tray 102 as a single integrated piece.

FIG. 4 is an upper side perspective view of an assembled collapsibleshelf assembly 400 in the open position in accordance with the presentinvention.

The peripheral sidewalls 402, 404 (or side members) span the length,bread or width of one edge of the base member 118. These sidewalls 402,404 are fabricated from a rigid or semi-flexible, polymeric orpolymerically-enveloped material, such as nylon or fiberglass. In otherembodiments, the sidewalls 104 may be fabricated from, or partiallyfabricated from, organic materials such as wood, latex or naturalrubber. The tray 102, 104, 106, 108 may be insulated. Alternatively, thetrays 102-108 may be pressed from sheet metal in other embodiments. Instill further embodiments, the trays 102-108 are formed from wovenelastomeric threads as known to those of skill in the art.

In various embodiments, the peripheral sidewalls 402, 404 are formedwith the base member 118 of the tray 102 as a single integrated piece.The tray 102 may be formed using means known to those of skill in theart, including through injection molding, additive manufacturing (i.e.,3D printing), extrusion processes, heat press, or other means known tothose of skill in the art.

The superior edges of the sidewalls 302, 402, 404 terminate with arounded, chamfered, angled, tapered or an otherwise-shaped uniform cutor edging.

FIG. 5 is a lower perspective view of an assembled collapsible shelf 500or shelf assembly in a partially-retracted position accordance with thepresent invention.

The shelf 500 collapses as shown.

FIG. 6 is a lower perspective view of an assembled collapsible shelfassembly in a partially-retracted position accordance with the presentinvention.

The tabs 120 within the tracks 112 or guide tracks 110, 114 acts as hardstops to prevent over-retraction of adjacent trays 102, 104, 106, 108.In the hard stop configuration, the tabs 120 are indicated at 602.

FIG. 7 is an upper side perspective view of an assembled collapsibleshelf assembly 700 in a partially-retracted position accordance with thepresent invention.

As shown. The trays 102-108 may stay in open or collapsed configurationby forming a friction fit one with another.

FIG. 8 is a side perspective view of an assembled collapsible shelfassembly 800 in a partially-retracted position accordance with thepresent invention; and

As shown with tray 108 overlapping tray 102.

FIG. 9 is a side perspective view of an assembled collapsible shelfassembly 900 in a partially-retracted position accordance with thepresent invention.

As shown with the tray 102 underlapping tray 108.

The present invention may be embodied in other specific forms withoutdeparting from its spirit or essential characteristics. The describedembodiments are to be considered in all respects only as illustrativeand not restrictive. The scope of the invention is, therefore, indicatedby the appended claims rather than by the foregoing description. Allchanges which come within the meaning and range of equivalency of theclaims are to be embraced within their scope.

What is claimed is:
 1. A collapsible shelf assembly, the collapsibleshelf assembly comprising: a first tray defining two or morelaterally-running guide tracks, the first tray comprising: a generallyrectangular base member fabricated of rigid polymeric material; a firstsidewall affixed to a top surface of the base member, the first sidewallsuperiorly-protruding therefrom adapted provide lateral stability toarticles stored on the top surface; a second sidewall affixed to a topsurface of the base member, the second sidewall superiorly-protrudingtherefrom adapted provide lateral stability to articles stored on thetop surface; two or more protuberances adapted to slidably travel withina longitudinal guide track on an adjacent tray running perpendicularlyto the laterally-running guide tracks; a second tray defining one ormore laterally-running guide tracks and one or morelongitudinally-running guide tracks, the second tray comprising: agenerally rectangular base member fabricated of rigid polymericmaterial; a first sidewall affixed to a top surface of the base member,the first sidewall superiorly-protruding therefrom adapted providelateral stability to articles stored on the top surface; a secondsidewall affixed to a top surface of the base member, the secondsidewall superiorly-protruding therefrom adapted provide lateralstability to articles stored on the top surface; a third tray definingone or more longitudinally-running guide tracks, the third traycomprising: a generally rectangular base member fabricated of rigidpolymeric material; a first sidewall affixed to a top surface of thebase member, the first sidewall superiorly-protruding therefrom adaptedprovide lateral stability to articles stored on the top surface; asecond sidewall affixed to a top surface of the base member, the secondsidewall superiorly-protruding therefrom adapted provide lateralstability to articles stored on the top surface; two or moreprotuberances adapted to slidably travel within a laterally-runningguide track on an adjacent tray; a fourth tray comprising: a generallyrectangular base member fabricated of rigid polymeric material; a firstsidewall affixed to a top surface of the base member, the first sidewallsuperiorly-protruding therefrom adapted provide lateral stability toarticles stored on the top surface; a second sidewall affixed to a topsurface of the base member, the second sidewall superiorly-protrudingtherefrom adapted provide lateral stability to articles stored on thetop surface; four or more protuberances adapted to slidably travelwithin one or more guide tracks on an adjacent trays.
 2. The collapsibleshelf assembly of claim 1, wherein the base member, first sidewall andsecond sidewall of each tray are formed as a single integrated piece. 3.The collapsible shelf assembly of claim 1, wherein the base member ofeach tray is perforated.
 4. The collapsible shelf assembly of claim 1,wherein each tray is insulated.
 5. The collapsible shelf assembly ofclaim 1, wherein the protuberances are substantially one of cylindricaland conical.
 6. The collapsible shelf assembly of claim 1, wherein thetrays form a friction fit one with another in a collapsed configuration.7. A collapsible shelf, the collapsible shelf comprising: a first traydefining one or more laterally-running guide tracks, the first traycomprising: a planar base member fabricated of rigid polymeric material;a first sidewall affixed to a top surface of the base member, the firstsidewall superiorly-protruding therefrom adapted provide lateralstability to articles stored on the top surface; a second sidewallaffixed to a top surface of the base member, the second sidewallsuperiorly-protruding therefrom adapted provide lateral stability toarticles stored on the top surface; a second tray defining one or morelongitudinally-running guide tracks, the second tray comprising: aplanar base member fabricated of rigid polymeric material; a firstsidewall affixed to a top surface of the base member, the first sidewallsuperiorly-protruding therefrom adapted provide lateral stability toarticles stored on the top surface; a second sidewall affixed to a topsurface of the base member, the second sidewall superiorly-protrudingtherefrom adapted provide lateral stability to articles stored on thetop surface; a third tray defining one or more longitudinally-runningguide tracks, the third tray comprising: a planar base member fabricatedof rigid polymeric material; a first sidewall affixed to a top surfaceof the base member, the first sidewall superiorly-protruding therefromadapted provide lateral stability to articles stored on the top surface;a second sidewall affixed to a top surface of the base member, thesecond sidewall superiorly-protruding therefrom adapted provide lateralstability to articles stored on the top surface; a track for slidablyengaging one of a longitudinally-running guide track and alaterally-running guide track on an adjacent tray; a fourth traycomprising: a planar base member fabricated of rigid polymeric material;a first sidewall affixed to a top surface of the base member, the firstsidewall superiorly-protruding therefrom adapted provide lateralstability to articles stored on the top surface; a second sidewallaffixed to a top surface of the base member, the second sidewallsuperiorly-protruding therefrom adapted provide lateral stability toarticles stored on the top surface; a track for slidably engaging one ofa longitudinally-running guide track and a laterally-running guide trackon an adjacent tray.
 8. The shelf of claim 7, wherein each tray slidablymates with two other trays.
 9. The collapsible shelf assembly of claim7, wherein the base member, first sidewall and second sidewall of eachtray are formed as a single integrated piece.
 10. A collapsible shelf,the collapsible shelf comprising: a first tray defining one or moreguide tracks, the first tray comprising: a planar base member fabricatedof rigid polymeric material having four sides; an L-shaped sidewallaffixed to a top surface of the base member, the L-shaped sidewallsuperiorly-protruding therefrom and covering two of the four sides ofthe base member; a second tray defining one or more guide tracks, thesecond tray comprising: a planar base member fabricated of rigidpolymeric material having four sides; one or more guide tracks forslidably receiving track on an adjacent tray; a third tray defining oneor more guide tracks, the third tray comprising: a planar base memberfabricated of rigid polymeric material having four sides; an L-shapedsidewall affixed to a top surface of the base member, the L-shapedsidewall superiorly-protruding therefrom and covering two of the foursides of the base member; a fourth tray defining one or more guidetracks, the fourth tray comprising: a planar base member fabricated ofrigid polymeric material having four sides; an L-shaped sidewall affixedto a top surface of the base member, the L-shaped sidewallsuperiorly-protruding therefrom and covering two of the four sides ofthe base member; wherein each tray slidably mates with two other trays.11. The collapsible shelf assembly of claim 9, wherein the base member,first sidewall and second sidewall of each tray are formed as a singleintegrated piece.